Bacteria don't just swim about randomly. Rather, they aim to find "good" environments and avoid "bad" ones. For example, they seek nutritious chemicals and shun noxious ones. This aspect of behavior is called "chemotaxis". Chemotaxis is the movement of organisms toward or away from chemicals. The major objective of this research is to try to understand the mechanism of chemotaxis. How do bacteria sense the chemicals that attract or repel them? How is the sensed information translated into action? How are the flagella told what to do? How do flagella work and how are they coordinated? The mechanism of motility is thus involved here too. The tools of biochemistry and genetics will be applied to try to answer these questions. In a broader way, the objective of this work is to try to understand the biochemical and genetic bases of behavior. Though bacteria are the organisms to be organisms. Applications of this work are conceivable in the area of neurological and psychiatric disorders. Chemotaxis may also be important in guiding the movement of cells during the growth of an embryo. Applications are thus conceivable in the area of abnormal growth -- cancer and the spread of cancer cells. Results of studies on chemotaxis in bacteria may also be applicable to learning about chemotaxis in leukocytes.